2. what is high-quality programming code? - code correctness, readability, maintainability

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High-Quality Code @ Telerik Academy Telerik Software Academy: http://codecourse.telerik.com/ The website and all video materials are in Bulgarian Content: What is High-Quality Programming Code? Why Quality Is Important? Software Quality What is High-Quality Programming Code? Code Conventions Managing Complexity Key Characteristics of High-Quality Code

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  • 1. What is High-Quality Programming Code? Code Correctness, Readability, MaintainabilitySvetlin NakovManager Technical Traininghttp://www.nakov.comTelerik Software Academyacademy.telerik.com
  • 2. What is High-QualityProgramming Code?
  • 3. Why Quality Is Important?static void Main(){ int value=010, i=5, w; switch(value){case10:w=5;Console.WriteLine(w);break;case 9:i=0;break; case 8:Console.WriteLine("8 ");break; default:Console.WriteLine("def ");{ Console.WriteLine("hoho "); } for (int k = 0; k < i; k++,Console.WriteLine(k - f));break;} {Console.WriteLine("loop!"); }}What does this code do? Is it correct? 3
  • 4. Why Quality Is Important? (2) static void Main() { int value = 010, i = 5, w; switch (value) { case 10: w = 5; Console.WriteLine(w); break; case 9: i = 0; break; case 8: Console.WriteLine("8 "); break; default: Console.WriteLine("def "); Console.WriteLine("hoho "); for (int k = 0; k < i; k++, Console.WriteLine(k - f)) ; break; } Console.WriteLine("loop!"); }Now the code is formatted, but is still unclear. 4
  • 5. Software Quality External quality Does the software behave correctly? Are the produced results correct? Does the software run fast? Is the software UI easy-to-use? Internal quality Is the code easy to read and understand? Is the code well structured? Is the code easy to modify? 5
  • 6. What is High-Quality Programming Code? High-quality programming code: Easy to read and understand Easy to modify and maintain Correct behavior in all cases Well tested Well architectured and designed Well documented Self-documenting code Well formatted 6
  • 7. What is High-Quality Programming Code? (2) High-quality programming code: Strong cohesion at all levels: modules, classes, methods, etc. Single unit is responsible for single task Loose coupling between modules, classes, methods, etc. Units are independent one of another Good formatting Good names for classes, methods, variables, etc. Self-documenting code style 7
  • 8. Code Conventions Code conventions are formal guidelines about the style of the source code: Code formatting conventions Indentation, whitespace, etc. Naming conventions PascalCase or camelCase, prefixes, suffixes, etc. Best practices Classes, interfaces, enumerations, structures, inheritance, exceptions, properties, events, constructors, fields, operators, etc. 8
  • 9. Code Conventions (2) Microsoft has official code conventions called Design Guidelines for Developing Class Libraries: http://msdn.microsoft.com/en-us/library/ms229042.aspx Sun also have official code conventions called Code Conventions for the Java Programming Language: http://java.sun.com/docs/codeconv/ Large organization follow strict conventions Code conventions can vary in different teams High-quality code goes beyond code conventions Software quality is a way of thinking! 9
  • 10. Managing Complexity Managing complexity has central role in software construction Minimize the amount of complexity that anyones brain has to deal with at certain time Architecture and design challenges Design modules and classes to reduce complexity Code construction challenges Apply good software construction practices: classes, methods, variables, naming, statements, error handling, formatting, comments, etc. 10
  • 11. Managing Complexity (2) Key to being an effective programmer: Maximizing the portion of a program that you can safely ignore while working on any one section of code Most practices discussed later propose ways to achieve this important goal 11
  • 12. Key Characteristics of High-Quality Code Correct behavior Conforming to the requirements Stable, no hangs, no crashes Bug free Correct response to incorrect usage Easy to read Easy to understand Maintainable easy to modify when required 12
  • 13. Key Characteristics of High-Quality Code (2) Good identifiers names Good names for variables, constants, methods, parameters, classes, structures, fields, properties, interfaces, structures, enumerations, namespaces, High-quality classes, interfaces and class hierarchies Good abstraction and encapsulation Simplicity, reusability, minimal complexity Strong cohesion, loose coupling 13
  • 14. Key Characteristics of High-Quality Code (3) High-quality methods Reduced complexity, improved readability Good method names and parameter names Strong cohesion, loose coupling Variables, data, expressions and constants Minimal variable scope, span, live time Simple expressions Correctly used constants Correctly organized data 14
  • 15. Key Characteristics of High-Quality Code (4) Correctly used control structures Simple statements Simple conditional statements and simple conditions Well organized loops without deep nesting Good code formatting Reflecting the logical structure of the program Good formatting of classes, methods, blocks, whitespace, long lines, alignment, etc. 15
  • 16. Key Characteristics of High-Quality Code (5) High-quality documentation and comments Effective comments Self-documenting code Defensive programming and exceptions Ubiquitous use of defensive programming Well organized exception handling Code tuning and optimization Quality code instead of good performance Code performance when required 16
  • 17. Key Characteristics of High-Quality Code (6) Following the corporate code conventions Formatting and style, naming, etc. Domain-specific best practices Well tested and reviewed Well designed unit tests High code coverage High coverage with automated tests Passed code reviews and inspections 17
  • 18. What Is High-Quality Programming Code? , BG Coder - - online judge , ASP.NET - , , C#, .NET, ASP.NET http://academy.telerik.com ASP.NET MVC HTML, SQL, C#, .NET, ASP.NET MVC SEO - , , iPhone, Android, WP7, PhoneGap , HTML, CSS, JavaScript, Photoshop - free C# book, C#, Java,

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